mtg: Kuldotha Rebirth & artifact in what order are they put in graveyard?

Part of the cost to cast Kuldotha Rebirth is to put an artifact from play into the graveyard. The Artifact will be in the graveyard long before Kuldotha Rebirth has finished resolving and goes to the graveyard.

Ignore anyone that says you can rearrange your graveyard to suit your needs because Bosium Strip exists in a format that says that it is illegal to rearrange your graveyard.

Well, you could certainly use Kuldotha Rebirth twice in that case, were you to have two artifacts in play. You could even use the Strip's ability, cast Rebirth, sac the Strip to it, cast it again, then sacrifice another artifact.

When something is sacrificed it goes straight to the graveyard before any abilities even resolve.